The best advice is don't try to cut the student slack by handling it on your own. It might blow-up in your face like it did for this professor. Instead, follow process. Report the student and let the "system" work.

Here's a first-hand account of how a teacher's best intentions can go horribly wrong when it comes to handling student plagiarism. It's from an essay called "Student Cheats and Those Who Harbor Them" found at 60 J. Legal Edu. 664 (2011) by - are you ready? - Sue D. Naim. Get it?

Here's an excerpt:

I had it on good authority that many schools give students the option for informal resolutions once administrators get their hands on these cases, so why not handle it myself? Settlements and plea bargains have their reasonable opponents, but in this context with this moral landscape, it seemed defensible. I wasn’t surprised to learn later that studies of student cheating reveal that faculty “underutilize” formal processes and come up with their own resolutions. I thought I would punish the student by awarding the exam a failing grade—and if the student was willing to accept the failure and not contest it, I would not report the cheating to the administration.

When I shared with colleagues that I was considering this solution, many supported me, thinking it was merciful and fair. Others thought it was too generous to the student. But no one suggested it was morally impermissible, which was interesting in its own right. Colleagues had ideas about what they might do and what they have done in similar situations, but most respected that these were hard questions with a range of morally permissible answers.

. . . .

I was expecting contrition and gratitude. And rationality. These were too much to hope for, alas.

. . . .

Denial was followed with fabricated documentary “evidence” to cover up the cheating, which only confirmed my belief that the cheating actually occurred. In the course of mounting a defense by email (the phone call did not prevent follow-up writings), Dani stupidly conceded to violating the local honor code in lesser ways (ways I actually wouldn’t have failed a student for), showing a pattern of disregard for exam rules. And then came the threats: Dani made explicit what I latently feared might result from reporting the episode to the administration. First, the student re-characterized my generous offer as an abuse of power and professional misconduct because I was threatening to fail the student no matter what. Then the student pointed out something that wasn’t actually untrue: I was willing to cheat the university (in a sense) by not giving Dani due process and just awarding an F. Suddenly, I was starting to think that I had now acted in a way that might make me look bad when it all came to light.

. . . .

My effort here has been to bring into the open something we will all face, hopefully infrequently but probably more than once. But I am also exploring my ambivalence here with the hope that it might actually be therapeutic for others, too. And it might just get administrations to realize that professors need them to provide better training and to vindicate our academic values.I spent several hours during my visiting appointment being trained on how not to engage in sexual harassment in the workplace; a half hour on what to do with student cheats really would have been time better spent.